THE IROQUOIS BEACH. 



125 



greater iu size than the area of the modern lake, but its margins have been less fully- 

 explored than those given upon the map. 



VZ^^Z^^^TZ^^TTTTT-. 



/////yy / /?j ^ ^ / / ^ , , ■ 



Fig. 1.— LoNfUTUWN.iL Section of L.vke Ieoquois between Hamilton {H) and Cape Rutland (fi).— The differen- 

 tial elevation of the eastern end over that of the western, now amounts to about 337 feet, i/ 7?, surface of 

 Lal<e Iroquois ; B If, surface of Lake Ontario, with outlet vXStL; S L, sea-level ; D, buried channels at the 

 mouth of the Erigan River (ancient outlet of the basin of L.ake Erie.) 



EiG. 2. — Section across the cbnteb or the lake from Teenton southward. — Tand Sd, surface of Lake Iroquois 

 DW, surface of Lake Ontario ; S L, sea-level ; D, hills of drift. 



Pig. 3. — Section across the lake showing the Escarpment at the bastbrn end op the basin, upoo the flank of 

 which the now sloping Iroquois Beach {C'C) rests. St L, the modern outlet; «Si, sea-level; O, position of 

 Oneida Lake ; C, position of the bed of Mohawk valley. The dotted line represents the relative position of the 

 floor of the St. Lawrence valley, compared with the lowest part of the bed of the basin — now occupied by the 

 modern lake ; at tlie commencement of the Iroquois epoch. Thus, what is now the rocky barrier, closing 

 Ontario into a basin, was then only from 150 to 2.50 feet above the deepest part of the lake : and thi.s was still 

 further reduced by something between 120 and 2-10 feet in the ancient channel of the St. Lawrence, which was 

 thus nearly or quite as low as the lowest part of the lake floor. 



The north-eastern extension of the lake was filled with islands, and had an average 

 depth of, probably, not over 250 or 300 feet. The rest of the lake, free from islands, was 

 deeper than at present, with a maximum sounding of 1,000' feet, in place of '728 feet as at 

 present found north-east of Pultneyville, N. Y. North of Cape Eutlaud the deepest 

 sounding was 24 miles distant, amongst what are now the Thousand Islands of the modern 



' 738 ft., deepest modern sounding ; 210 ft., measured height of beach, south of sounding, above lake, phis 

 52 ft. calculated elevation of water-level, at the position of the deepest sounding, above its beach to the south. 



